Stator of rotating electric machine

Abstract

The present invention relates to a stator of a rotating electric machine, including: a stator core having a plurality of slots; and a stator coil configured by connecting a plurality of conductor segments including: one or more first-type conductor segments each having a conductor and a first sheath part surrounding and insulating an outer surface of the conductor; and one or more second-type conductor segments each having the conductor, the first sheath part, and a second sheath part surrounding and insulating a part of an outer surface of the first sheath part, wherein each of the conductor segments includes two insertion parts configured to be inserted into different slots among the plurality of slots; a crown part connecting respective first ends of the two insertion parts; and welding parts extending from respective second ends of the two insertion parts to be connected by welding, and wherein the second-type conductor segment is disposed in a section having a relatively high voltage distribution ratio. Therefore, during high voltage application, partial discharge can be prevented.

The invention claimed is: 
     
         1 . A stator of a rotating electric machine, the stator comprising:
 a stator core having a plurality of slots; and   a stator coil configured by connecting a plurality of conductor segments comprising:   one or more first-type conductor segments each having a conductor and a first sheath part surrounding and insulating an outer surface of the conductor; and   one or more second-type conductor segments each having a conductor, a first sheath part, and a second sheath part surrounding and insulating a part of an outer surface of the first sheath part,   wherein each of the conductor segments comprises:   two insertion parts configured to be inserted into different slots among the plurality of slots;   a crown part connecting respective first ends of the two insertion parts; and   welding parts extending from respective second ends of the two insertion parts to be connected by welding, and   wherein the second-type conductor segment is disposed in a section having a relatively high voltage distribution ratio, and   wherein the first sheath parts of the first-type conductor segments and the second-type conductor segments are formed to surround an entire length of the conductor segment, and   wherein the second sheath part of the second-type conductor segments is formed to surround the first sheath part at the crown part, and   wherein the second sheath part comprises:   a first section and a second section having different average thicknesses,   wherein the first section includes a center bending part, and   wherein the first section has a greater coating thickness compared to the second section.   
     
     
         2 . The stator of  claim 1 , wherein the stator coil comprises:
 a plurality of phase power lines respectively connected to a three-phase AC power source, wherein a plurality of phase coils are connected to the plurality of phase power lines, and   wherein the stator coil comprises a plurality of layers spaced apart inside the slot along a radial direction of the stator core, and   wherein the plurality of phase power lines are connected to a conductor segment disposed at an outermost layer among the plurality of layers of the phase coils.   
     
     
         3 . The stator of  claim 2 , wherein the plurality of layers comprise a first layer to an eighth layer,
 wherein the eighth layer is disposed at an outermost side along the slot, and   wherein a conductor segment of the second-type conductor segment is disposed in the eighth layer.   
     
     
         4 . The stator of  claim 2 , wherein the plurality of phase coils comprise:
 a first coil part to an n-th coil part each having a plurality of conductor segments connected in series, and   wherein a conductor segment disposed in a first section to which one of the plurality of phase power lines is connected is a second-type conductor segment.   
     
     
         5 . The stator of  claim 4 , wherein the first section includes the first coil part having a voltage distribution ratio of 60% or more. 
     
     
         6 . The stator of  claim 4 , wherein the first section comprises:
 the first coil part having a voltage distribution ratio of 60% or more and a second coil part connected in series to the first coil part and having a voltage distribution ratio of 50% or more.   
     
     
         7 . The stator of  claim 1 , wherein an insulation distance between respective first sheath parts of conductor segments having different phases disposed at the outermost layer is 400 μm or more. 
     
     
         8 . The stator of  claim 7 , wherein the crown part of a second-type conductor segment disposed at the outermost layer has the center bending part protruding along an axial direction and inclined sections connecting the bending part and the respective first ends of the two insertion parts. 
     
     
         9 . The stator of  claim 1 , wherein a minimum thickness of the second sheath part of the second-type conductor segment disposed at the outermost layer is 200 μm or more. 
     
     
         10 . The stator of  claim 1 , wherein the second sheath part is formed by impregnating the bending part of the second-type conductor segment into a solution forming the second sheath part. 
     
     
         11 . The stator of  claim 1 , wherein the first sheath part is formed of enamel and the second sheath part is formed of epoxy. 
     
     
         12 . The stator of  claim 1 , wherein the stator coil comprises:
 coil ends protruding from both ends of the stator core along an axial direction; and   a molding part formed to surround the coil ends with an electrical insulating member.   
     
     
         13 . The stator of  claim 12 , wherein the molding part is vacuum-formed to allow air around the coil end to be discharged.